A vaginal probe is a small ultrasound transducer (e.g. a biplane probe) that is inserted directly into the vagina. A sterile cover is slipped over the handheld transducer (also handle or probe), which is then covered with lubricating gel and placed in the vagina.
This technique produces a sharp image, not only because of the close proximity to the uterus, but also because this transducer is more sensitive.

Biplane endorectal and endovaginal probes are commonly used in obstetrics, gynecology and urology. They are generally composed of 2 arrays one linear for imaging of the longitudinal plane and a highly curved one to image the transverse plane. These two planes allow a perpendicular visualization of the region of interest.
Ultrasound imaging in both transverse and longitudinal planes enables e.g., precise multiple biopsies by simultaneous visualization of both planes in real-time.

The usual applications of endocavitary echography (also called internal echography / endoscopic ultrasound (EUS)) are examinations of the pelvic organs through internally introduced probes, which give a more precise and correct image.
Transrectal ultrasound is a well established method for rectal or prostate carcinoma assessment.
A transvaginal echography uses a small transducer that is inserted directly into the vagina.
Used are high-frequency (10-12 MHz) for superficial organs, endocavitary echography, and intraoperative laparoscopic ultrasound. A sterile cover is slipped over the probe, which is then covered with lubricating ultrasound gel and placed in the cavitary (see Equipment Preparation).

See also Endoscopic Ultrasound, Prostate Ultrasound, Interventional Ultrasound, Transurethral Sonography, Vaginal Probe, Rectal Probe.

Gynecologic ultrasound and obstetric ultrasound are two distinct applications of ultrasound imaging that serve different purposes in the field of women's health. While both involve the use of ultrasound technology to examine the pelvic region, they have different focuses and objectives.

Gynecologic [gynaecologic, Brit.] ultrasound primarily concentrates on the evaluation of the female reproductive organs, including the uterus, ovaries, fallopian tubes, and surrounding structures. It is commonly performed for various gynecological concerns, such as abnormal bleeding, pelvic pain, infertility investigations, and monitoring of reproductive disorders. It can identify signs of inflammation, the presence of free fluid, cysts, and tumors. This non-invasive technique aids in diagnosing and monitoring gynecological pathologies, facilitating early intervention and appropriate treatment. Typically, a transabdominal sonogram is performed with a full bladder to provide an initial assessment. However, if the pelvic ultrasound reveals any abnormalities or fails to provide a clear image of the organs, a more detailed evaluation can be achieved through a transvaginal sonography. This approach allows for improved visualization of the uterus and ovaries by placing the ultrasound probe inside the vagina.

Obstetric ultrasound, also known as prenatal, fetal or pregnancy ultrasound, is the branch of medical imaging that focuses on the use of ultrasound technology to assess the health and development of a fetus during pregnancy. Women with uncomplicated pregnancies commonly undergo an ultrasound examination between the 16th and 20th week of gestation. This routine assessment, performed with a real-time scanner, serves to determine accurate gestational age, monitor fetal size, and assess overall growth. The middle of the pregnancy trimester provides a crucial window for detecting many abnormalities of fetal anatomy. Advanced imaging techniques enable healthcare professionals to identify potential structural issues. Early detection of these abnormalities allows for timely intervention, counseling, and the implementation of appropriate management strategies.
See also Pregnancy Ultrasound, Pelvic Ultrasound, Hysterosalpingo Contrast Sonography and Vaginal Probe.

Pregnancy ultrasound plays a crucial role in monitoring the health and development of the fetus throughout pregnancy. It serves as a screening tool with various applications, including:

See also Doppler Fluximetry in Pregnancy, Fetal Ultrasound, Obstetric and Gynecologic Ultrasound and Vaginal Probe.